One Plant, Three Seasons: Iris ‘Gerald Darby’

Iris 'Gerald Darby' at Hayefield

Irises as a group aren’t among my favorite plants. The individual flowers are exquisite, of course, but the flowering period isn’t all that long, and many of them just aren’t all that interesting when they aren’t in bloom. There are exceptions, though. One that I’ve found to earn its keep through much of the growing season is ‘Gerald Darby’.

This selection is most often listed under Iris x robusta – a hybrid of two native American species: I. versicolor and I. virginica – though you’ll sometimes see it sold as a cultivar of one of those parent species, or as a Siberian-Louisiana Hybrid. It’s been around since the late ’60s but still isn’t widely available, and I can’t imagine why, considering how many good qualities it has to offer.

‘Gerald Darby’ in Spring

The best ornamental feature of this selection is its spring foliage, which ranges from dusky purple to purple-black (usually, the cooler the weather, the darker the foliage).

Iris 'Gerald Darby' at Hayefield

Above is ‘Gerald Darby’ with ‘Angelina’ sedum (Sedum rupestre) [April 19, 2009]. Below is a much quieter combination of ‘Gerald Darby’ with purple-leaved Japanese parsley or Japanese honewort (Cryptotaenia japonica f. atropurpurea) [April 11, 2010].

Iris 'Gerald Darby' at Hayefield

The growing tips are bright green, but the purple lingers at the base of the plants for a few more weeks. Below is a shot from May 1, 2008. At this point, the plants were 12 to 18 inches tall. You can see that some of the leaves are already starting to arch.

Iris 'Gerald Darby' at Hayefield

By late May, the leafy clumps are about 3 feet tall. The purple at the leaf bases is hardly noticeable at this point, but there’s a new source of interest: slender but sturdy, near-black flowering stems that spike up through the foliage.

Iris 'Gerald Darby' at Hayefield

The images above and below are from May 22, 2010. The one below – a later view of the April 11 shot with purple-leaved Japanese parsley – also includes some shoots of blue-leaved rose (Rosa glauca).

Iris 'Gerald Darby' at Hayefield

‘Gerald Darby’ in Summer

Early summer is prime time for the bloom display of ‘Gerald Darby’ here in southeastern Pennsylvania. Each stalk usually carries several buds, so there’s a good show of nicely distributed flowers. Below is a June 1 shot of the combo also featured above.

Iris 'Gerald Darby' at Hayefield

The flowers are rather delicate-looking, and the purple-blue color isn’t especially vibrant. For a few years, my original clump flowered against a clump of ‘Amazone’ tuberous Jerusalem sage (Phlomis tuberosa) [below: June 1, 2006].

Iris 'Gerald Darby' at Hayefield

The pairing was pretty but wispy and not “wow.” Fortunately, the vigorous plants bulk up quickly, so within a few years, I had enough divisions to be able to experiment with different settings.

Adding some dark foliage gave the flowers a much more interesting background. The image below, from June 28, 2010, includes a red Japanese maple (Acer palmatum).

Iris 'Gerald Darby' at Hayefield

Iris 'Gerald Darby' at Hayefield

Above is ‘Gerald Darby’ against Diabolo ninebark (Physocarpus opulifolius ‘Monlo’), which did a great job of echoing the dark staining in the iris stems [May 26, 2010]. Below, the background is ‘Velvet Cloak’ smokebush (Cotinus coggygria) [May 23, 2010].

Iris 'Gerald Darby' at Hayefield

Chartreuse foliage did an even better job creating the wow factor I was hoping for.

Iris 'Gerald Darby' at Hayefield

Below is a shot from June 13, 2009, with ‘Angelina’ sedum and golden catalpa (Catalpa bignonioides ‘Aurea’).

Iris 'Gerald Darby' at Hayefield

‘Gerald Darby’ in Fall

After flowering, this iris rarely sets seed, so it’s just a foliage accent – a job it does quite well as long is the weather isn’t too dry. My soil tends to be on the moist side but has some dry periods each summer and it normally continues to look good for months. The image below is from August 23, 2006.

Iris 'Gerald Darby' at Hayefield

For comparison, here’s a view of that same area of the garden: from June 26, 2006 on the left and September 19, 2006 on the right.

Iris 'Gerald Darby' at Hayefield Iris 'Gerald Darby' at Hayefield

By mid-fall – or earlier if the weather is very dry – the clumps collapse messily [below, October 22, 2006]. Still, that seems a fair exchange for the extended show of new shoots, flowers, and foliage.

Iris 'Gerald Darby' at Hayefield

Before the collapse, ‘Gerald Darby’ usually reaches about 4 feet tall for me, but I’ve seen the leafy clumps reach 5 feet or more in very rich, moist soil. It’s reportedly hardy in Zones 4 to 9.

Current web sources for ‘Gerald Darby’ include ForestFarm, Secret Garden Growers, and McClure & Zimmerman. If you have trouble finding it, you might consider trying a cultivar called ‘Dark Aura’ instead; I’ve not seen it in person, but the descriptions make it sound just like ‘Gerald Darby’. ‘Dark Aura’ is currently listed by Plant Delights Nursery and Iris City Gardens.

21 responses to this post.

  1. That spring foliage is stunning! I’d heard of this iris, but the foliage didn’t sound that amazing. Now that I’ve seen it in your pictures, though, I think I’m going to have to add it to my spring plant orders. Thanks, as always, for cluing me in on such amazing plants!

    Wow, Joseph – that was quick. I glad you found this iris enticing. I’m sure you won’t be disappointed.
    -Nan

  2. Oh Nan…you always have the most drool-worthy plants that send me scurrying to find them (I was happy to see this on the Forest Farm site, which has great quality plants). I love that purplish foliage in spring…and the dark stems…stunning. I agree that the downfall of most Iris is their lack of seasonal interest (beyond flowering). Thanks again for the inspiration…I’m thinking this would look great behind my ‘Powis Castle’ Artemisia.

    I really appreciate the ForestFarm lead, Scott. I’ve added it to the list of possible sources above. I can imagine that ‘Gerald Darby’ would look fantastic with ‘Powis Castle’ from a color and textural standpoint, but I’m not sure how they’ll do culturally. I have trouble keeping ‘Powis Castle’ going in the same area that the iris thrives in. Still, it’s worth a try; you may be able to find a good compromise. Good luck!
    -Nan

  3. As I type, there’s a stack of catalogues for tonight’s reading at my elbow, McClure & Zimmerman on the top, and I can’t wait to see if this amazing iris is listed this year. I’m sold!

    Check out Page 22, Denise. ‘Gerald Darby’ is also listed on their web site as of today (link above in the post), so it should be available. Enjoy!
    -Nan

  4. What a fantastic plant, though I need to ponder the moisture requirements, I wonder how it would fare in a summer drought climate ? That purple action at the base is oo-la-la !

    Our summers are normally pretty dry here too, Kathy, but my soil is on the silty/clayey side, so that probably helps it survive. I imagine that mulching heavily could help, if you decide to give it a try. Another option would be to plant it in a bog or water garden (it can grow in several inches of standing water), or in a container.
    -Nan

  5. Nan, an inspiring iris indeed. I adore those black stems and purple base leaves. And you certainly found good companions for it.

    Thanks, Pam. I’ve been thinking that it could look terrific in one of those galvanized metal troughs that you like to use.
    -Nan

  6. That’s a beautiful Iris. The flowers are very similar to the ones I have growing in my pond as a marginal, but mine don’t have the stunning dark stems. They do have the most amazing red seeds though – does ‘Gerald Darby’?

    Unfortunately, no. In the last 6 or 7 years, I’ve seen maybe three seedpods form but never any seed; the developing pods just withered away.
    -Nan

  7. I bought two plants of `Dark Aura´ from USA two years ago, together with 10 others (which already were died when they arrived). The leafs and the flowers are very nice, but I have to move them from the elevated bed. I think they need more moisture.

    I bet you’re right, Susie. Its preference for moisture is a big plus for heavier soils, and winter wet doesn’t bother it at all. I’d save a raised bed for plants that demand good drainage.
    -Nan

  8. Siberian iris is one of my favourite plants, so of course I love this one and it has been added to my list of plants to look for. I am sure that it will perform well here in my wet clay garden.
    Lene

    It sounds like you have the ideal conditions for this iris, Lene. I’m sure it will be a lovely addition to your collection. Wouldn’t it be great to have some of the flower colors of Siberians combined with the purple foliage feature?
    -Nan

  9. Nan: Yet another plant I need to add to my “must have” list! We have similar opinions of most irises: They don’t have a long enough bloom season. I think I’d grow this one even if it didn’t bloom. Love the black stems and clumps of purplish foliage. Barbara

    Hey, Barbara. You’re right: it doesn’t even need to flower to earn a place in the garden. That’s a nice bonus, though.
    -Nan

  10. Posted by Lisa at Greenbow on January 20, 2011 at 10:23 am

    Oh be still my heart. I love Irises and this dark foliage is outstanding. I will have to look for him.

    He’s worth hunting for, Lisa. Even if you can get only a single fan, you’ll be amazed at how quickly he forms sizable clumps.
    -Nan

  11. WOW! Never seen this one before. Has been immediately added to my ‘Must Have’ list. Thanks so much for sharing.

    My pleasure, Laura. I’m thrilled that so many readers find this iris as fantastic as I do!
    -Nan

  12. This is beautiful. I don’t think I’ve seen an iris with such dark foliage.

    Until I wrote this post, I thought ‘Gerald Darby’ was unique – then I found the listings for ‘Dark Aura’. It would be great to get that foliage into other cultivars.
    -Nan

  13. I love all kinds of iris, short-bloomed as they may be. Maybe we could do a plant trade since we are so close. I have a ninebark just waiting to set something off.

    I’m sure that can be arranged, Carolyn!
    -Nan

  14. Very cool! I love the black foliage. Irises are very cool but the foliage is usually what is lacking. That’s one I’ll have to add!

    It’ll look great at your place, Dave, and you’ll be pleased at how easy it is to propagate.
    -Nan

  15. It is not just the plant that is so lovely, it is your way with the winning combinations. Great info and the pics are sublime.

    You’re so kind, Layanee. It’s all trial and error, as you know – well, and luck too.
    -Nan

  16. WOW!!!! What a gorgeous plant!! It looks like my spring Plants I Can NOT Live Without list is about to get a bit longer. Thank you!!! Now to find the perfect spot… :o)

    Ah hah – another victim falls under Gerald’s spell. What fun to enable fellow gardeners to spend money. (Hey, we’re supporting the nursery industry, right?)
    -Nan

  17. Nan, that is positively gorgeous! I am going to order 4. I for me (hot dry garden) and 3 for the Idaho Botanical Garden. I’ve always wanted to include some Louisiana/Serbians in the Contemporary English Garden and we have some damper spots that I think would be perfect. Thanks so much for showcasing this beauty. The dark stems and foliage are lovely.

    Out of four, you should certainly have success with some of them. A generous layer of mulch and perhaps some afternoon shade may help the one you plant at home. Worth a try, anyway. You might also want to avoid putting it in a high-visibility spot in case very hot and dry weather causes the foliage to fizzle out early.
    -Nan

  18. Posted by Prairie Girl on January 28, 2011 at 10:50 am

    Love the color combo with the daffodils and ‘Angelina’ sedum, that is my current fave duo: Deep purple & Pale yellow! So far I only have two irises, both bearded, a tall red-flowered one, and ‘Immortality’. I have had great difficulty trying to blend them into my meadow-style garden of long-blooming plants. Looks like the Siberians will do better in clay, and make larger clumps faster? Since ‘Gerald Darby’ has the bonus of that great purple foliage, another sucker born here, LOL.

    I too am a fan of ‘Immortality’, especially when it flowers again in the fall. But its flowers are so large and bright white that it really does look out of place with meadow-type plants, doesn’t it?
    -Nan

  19. Posted by Melanie on January 28, 2011 at 12:00 pm

    I just LOVE your blog. You inspire me. thanks.

    Welcome, Melanie. I hope you’ll visit again.
    -Nan

  20. The purple and chartreuse foliage really brings out the vibrance of those blooms and purple stems, Nan. Your experimental pairing paid off nicely with this lovely Iris. You’ve taken some beautiful shots to inspire us. Thanks for the great ideas.

    Thanks, Kerri. You sure can’t beat purple and chartreuse, can you?
    -Nan

  21. Laughing at myself. Just found Plant Delights 2010 catalog. Trying to decipher my own writing on the cover – the plants I wanted to make note of. #2 on the list? Iris x robusta ‘Dark Aura’!

    You clearly have excellent taste, Laura. Now that you know what you want, maybe you can try it this season.
    -Nan

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